Self-sealing fluid check valves are used in a variety of applications to control fluid flow through lines and devices, including in medical applications as components of gravity-fed and pump-driven intravenous infusion sets. Such check valves may be called “back check valves” or “non-return valves” or “one-way valves,” and typically include a feature such as a duckbill valve, a ball valve, or most, commonly, a disc valve which engages with an adjacent valve seat in response to fluid flow in a selected direction. In an infusion line, a check valve is frequently used to prevent fluid backflow during IV therapy, e.g., after disconnection of a fluid supply such as a suspended infusion bag, or to prevent cross-flow during the parallel infusion of solutions through a single patient infusion line. Conventional check valves may be suitable for infusing saline, dextrose, or IV-delivered pharmaceutical solutions, but can cause significant levels of hemolysis, i.e. significant rupturing of erythrocytes or so-called red blood cells, when used during the infusion of packed cells or whole blood products into a patient. This is because the tortuous fluid path from the valve inlet, against the check valve, through the check valve or around the periphery of the check valve, and then across the lee side of the valve produces substantial fluid pressure changes, turbulence, and, most importantly, microscale shear forces that stress the cell membranes of erythrocytes entrained within the infusion fluid. An exemplary model of such a valve illustrating a flow velocity field and, indirectly, shear forces caused by flow velocity gradients is shown in FIG. 1 for reference.